Association of Primary Open-Angle Glaucoma with Diabetic Retinopathy among Patients with Type 1 and Type 2 Diabetes

PurposeTo assess the correlation between primary open-angle glaucoma (POAG) and the risk of developing diabetic retinopathy (DR) in patients with type 1 diabetes mellitus (T1DM) and type 2 diabetes mellitus (T2DM).DesignA retrospective cohort study leveraging the global patient database of TriNetX Research Network.ParticipantsThe study included 44 359 patients with diabetes mellitus (DM) with POAG and 4 393 300 patients with DM without any glaucoma ≥ 18 years of age. Propensity score matching harmonized the cohorts to 39 680 patients each, covering diagnoses from January 1, 2005, to January 1, 2023.MethodsWe analyzed data using specific International Classification of Diseases, 10th Revision (ICD-10) codes for DM and glaucoma. We matched the cohorts using propensity score matching, adjusting for age, sex, race/ethnicity, blood markers, relevant medical history, and ophthalmic service use.Main Outcome MeasuresThe primary outcome was the first-time occurrence of DR, including nonproliferative DR (NPDR) and proliferative DR (PDR), in patients with DM with and without glaucoma at 1-, 5-, and 10-year intervals from their individual index dates.ResultsAt 10 years, patients with T1DM with POAG exhibited a heightened risk for any DR (adjusted risk ratios [RRs], 4.12; 95% confidence interval [CI], 3.05–5.57, P < 0.0001) and PDR (RR, 7.02; 95% CI, 3.62–13.61, P < 0.0001). Patients with T2DM and POAG also faced an increased 10-year risk for any DR (RR, 2.47; 95% CI, 2.28–2.68, P < 0.0001) and PDR (RR, 3.82; 95% CI, 3.09–4.70, P < 0.0001). The combined association of POAG on DR risk in those with T1DM and T2DM at 10 years was found to be significantly higher among patients with POAG (5.45%) compared with those without glaucoma (2.12%) (adjusted hazard ratio [aHR], 2.33; 95% CI, 2.14–2.53). The cumulative incidence of DR was significantly higher in the POAG group compared with nonglaucoma counterparts after a decade (log-rank P < 0.001).ConclusionsOur findings underscore a substantial association between POAG and DR development in both T1DM and T2DM patients, emphasizing the need for vigilant screening and comprehensive management in glaucomatous patients with DM to mitigate the risk of DR. Future research should delve into elucidating the causal mechanisms driving these observed associations.Financial Disclosure(s)The author(s) have no proprietary or commercial interest in any materials discussed in this article.